A process for the preparation of methanol is described in U.S. Pat. No. 4,619,946 comprising reacting carbon monoxide and hydrogen at relatively low temperature in the presence of a catalytic system derived from sodium hydride, a sodium alcoholate and an acetate of nickel, palladium or cobalt. The alcoholate applied is preferably a lower alkanolate having 1-6 carbon atoms. As metal salt nickel acetate is preferably used. The catalyst is subjected to a conditioning or activating step for a prolonged time with a gaseous mixture comprising carbon monoxide and hydrogen at such an elevated temperature and elevated pressure that a substantial amount of carbon monoxide and hydrogen is consumed for this conditioning.
In U.S. Pat. No. 4,614,749 a process is disclosed for the preparation of methanol by reaction of carbon monoxide and hydrogen in the presence of a slurry catalyst system resulting from combination of (1) a reducing agent comprising sodium hydride-alcohol and an acetate of nickel, palladium or cobalt, and (2) a carbonyl complex of one of the group VI metals.
Another process for the preparation of methanol is described in Japanese Patent No. 56-169,634. This process comprises reacting carbon monoxide and hydrogen in the presence of a catalyst comprising a nickel compound and a metal alkoxide. The catalyst to be used for this process may be prepared by mixing a nickel compound with an alkali metal alkoxide. It is preferred to use a liquid organic diluent. It is observed that this Japanese application teaches a person skilled in the art, that a high reaction rate may be reached by preparing the catalyst system with the use of a substantially alcohol free organic diluent and that it is desirable that an alcohol be not present in the reaction system at the commencement of the reaction. Moreover from this Japanese patent application and especially from its example 2, it clearly appears that at low temperature only small amounts of methanol are produced in favour of production of methyl formate in large amounts.
In Japanese Patent No. 56-110631 a process is described for the preparation of methanol comprising the use of a catalytic system derived from a hydride, an alcoholate and a copper salt. Relatively high reaction temperatures and pressures are necessary in order to obtain a reasonable yield of methanol.
Although improvements in the performances of the catalyst systems as described hereinbefore, could be reached as compared to those used in the conventional methanol manufacturing processes, requiring severe conditions, the still growing demand for cheaper methanol as starting material for a still increasing area of chemical syntheses evoked continuing research efforts for a further improved methanol manufacturing process as compared to the currently operated high pressure processes.
With the term improved methanol manufacturing process is meant a process utilizing a catalyst having enhanced activity at low temperatures, and retaining its activity for a long time under economically more attractive operating conditions.
An object of the present invention is therefore to provide such an improved manufacturing process for methanol, as well as to provide an improved catalytic system therefor.